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From: jsdy@hadron.UUCP (Joseph S. D. Yao)
Newsgroups: net.lang.c
Subject: Re: functions that don't return
Message-ID: <1804@curly.ucla-cs.ARPA>
Date: Mon, 29-Sep-86 16:32:16 EDT
Article-I.D.: curly.1804
Posted: Mon Sep 29 16:32:16 1986
Date-Received: Sat, 4-Oct-86 06:02:41 EDT
References: <28@tl-vaxa.UUCP> <86900066@haddock>
Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao)
Organization: Hadron, Inc., Fairfax, VA
Lines: 26
Summary: How do you exit if you take away exit()?  Answer:

In article <86900066@haddock> karl@haddock writes:
>if you supersede exit() with a function that returns, how do you get out of
>the program?  Send yourself a signal?

Most crt0.s's or the like contain code similar to:

	store-args	argc, argv, envp
	call-function	_main
	call-function	_exit
	system-call	exit
	halt

If exit() is re-defined to return, the system call will exit after
a return from main().  The 'halt' usually causes a trap if neither
works.

Using 'return' from main() is the preferred way to exit according
to System V lint (which complains otherwise).  I've preferred it
myself, for years before, because I've viewed exit() as a glitch
in a smooth mental model of the invocation and return of routines.
THIS (latter) IS PURELY PERSONAL PREFERENCE, NO FLAMES DESIRED,
but comments on s5lint's and others' mental models welcome.
-- 

	Joe Yao		hadron!jsdy@seismo.{CSS.GOV,ARPA,UUCP}
			jsdy@hadron.COM (not yet domainised)